Just looking for a reality check here. I am trying to get an amp
running. It was not built by me and had apparently been sitting for
quite a while.
Everything seemed to be working but the input SWR wouldn't tune
below 4:1 with about 25W drive. I understand it will change some at
full power but I don't think this circuit is working as desired and
am reluctant to put my SS driver PA into it.
I pulled the bottom cover to look at the input circuit. It's the
usual T with two coils (not the usual dimensions) and shunt
capacitor between them. BUT, it is connected to the bottom
connection of the tube. I think that is the filament connection that
is NOT common to the cathode. There is NOT a capacitor across the
two filament/cathode connections. All of the circuits I could find
online this afternoon show the RF input to the next ring up on the
tube (filament/cathode common). Some show a capacitor across the
filament connections, some don't. Comments?
I am inclined to rip this out and rebuild. The 10 AWG hard silver
plated wire the coils are made from makes it impossible to spread or
compress turns to experiment with the match.
Thanks,
Paul
--
Paul
N1BUG 160m-2m DXCC Honor Roll
WI2XTC 2200m-630m Experimental license
FN55mf ME Piscataquis County
http://www.n1bug.com
http://www.aurorasentry.com
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